Verbosely describe the action for each file whose group actually
changes.

‘-f’

‘--silent’

‘--quiet’

Do not print error messages about files whose group cannot be
changed.

‘--dereference’

Do not act on symbolic links themselves but rather on what they point to.
This is the default.

‘-h’

‘--no-dereference’

Act on symbolic links themselves instead of what they point to.
This mode relies on the lchown system call.
On systems that do not provide the lchown system call,
chgrp fails when a file specified on the command line
is a symbolic link.
By default, no diagnostic is issued for symbolic links encountered
during a recursive traversal, but see --verbose.

‘--preserve-root’

Fail upon any attempt to recursively change the root directory, /.
Without --recursive, this option has no effect.
See Treating / specially.

Change the group of each file to be the same as that of
ref_file. If ref_file is a symbolic link, do not use the
group of the symbolic link, but rather that of the file it refers to.

‘-v’

‘--verbose’

Output a diagnostic for every file processed.
If a symbolic link is encountered during a recursive traversal
on a system without the lchown system call, and --no-dereference
is in effect, then issue a diagnostic saying neither the symbolic link nor
its referent is being changed.

‘-R’

‘--recursive’

Recursively change the group ownership of directories and their contents.

‘-H’

If --recursive (-R) is specified and
a command line argument is a symbolic link to a directory, traverse it.
See Traversing symlinks.

‘-L’

In a recursive traversal, traverse every symbolic link to a directory
that is encountered.
See Traversing symlinks.

‘-P’

Do not traverse any symbolic links.
This is the default if none of -H, -L,
or -P is specified.
See Traversing symlinks.

An exit status of zero indicates success,
and a nonzero value indicates failure.

Examples:

# Change the group of /u to "staff".
chgrp staff /u
# Change the group of /u and subfiles to "staff".
chgrp -hR staff /u